Coronary Angiography: Technique




Background


Despite major advances in other imaging modalities, invasive cardiac catheterization remains a critical component of cardiovascular care. More than 1.1 million cardiac catheterization procedures, in addition to approximately 1.3 million percutaneous coronary interventions (PCIs), were performed in the United States in 2006. Tremendous advances in digital imaging and procedural equipment have occurred since the last American College of Cardiology/American Heart Association (ACC/AHA) guidelines were published in 1999. This chapter aims to provide the reader with an overview of the practical fundamentals of performing invasive coronary angiography.




Indications for Performing Coronary Angiography


Selective catheterization of the left coronary artery and the right coronary artery (RCA), combined with intraarterial injection of radiopaque contrast media, allows radiographic imaging of the coronary arterial system. A complete assessment of coronary artery bypass grafts (arterial and venous) also entails selective cannulation and contrast media injection. Critical information concerning the presence (and burden) or absence of obstructive coronary artery disease (CAD) may be obtained from invasive coronary angiography. However, coronary angiography is a luminogram, which shows only the contrast-filled arterial lumen and densely calcified plaque. Noncalcified or lightly calcified nonobstructive atherosclerotic plaque may remain undetected in the absence of luminal narrowing. Although coronary angiography has undoubtedly had an impact on many aspects of cardiovascular care, the widespread availability of this imaging technique has perhaps influenced the management of patients with acute coronary syndrome the most. For example, primary PCI is the superior treatment modality for patients with acute ST-segment elevation myocardial infarction.


Detailed guidelines concerning indications for coronary angiography are summarized in Box 2-1 . This list is not meant to be exhaustive and serves merely to highlight some of the most common clinical indications for invasive coronary angiography. The reader is directed to the ACC/AHA guidelines for coronary angiography for further information. As can be seen from these comprehensive guidelines, risk stratification plays an important role in assessing patient suitability for invasive coronary angiography. A study of patients without known CAD who underwent coronary angiography from January 2004 through April 2008 examined almost 400,000 patients enrolled in the ACC National Cardiovascular Data Registry. The investigators defined obstructive CAD as stenosis of 50% or more of the diameter of the left main coronary artery (LMCA) or stenosis of 70% or more of the diameter of a major epicardial artery. No CAD (defined as <20% stenosis in all vessels) was found in 39.2% of all patients. Among those patients with a positive result on noninvasive testing, the number was 41%. The investigators concluded that better risk stratification is required in clinical practice to ensure a higher diagnostic yield.



BOX 2-1

Indications for Coronary Angiography


Patients With Known or Suspected Coronary Artery Disease Who Are Symptomatic or Have Stable Angina


Class 1





  • CCS class III and IV angina in patients receiving medical therapy



  • Presence of high-risk criteria on noninvasive testing



  • After cardiac arrest or in patients with sustained monomorphic VT or nonsustained polymorphic VT



Class IIa





  • CCS class III or IV angina that improves with medical therapy



  • Progressive worsening abnormalities on serial noninvasive testing



  • Patients with angina who are unsuitable for noninvasive testing



  • CCS I or II unresponsive to or in patients intolerant of medical therapy



  • Certain occupations with abnormal but not high-risk stress tests or those deemed high risk



Class IIb





  • CCS class I or II angina with known ischemia in the absence of high-risk criteria on noninvasive testing



  • Asymptomatic man or postmenopausal woman with two or more major clinical risk factors and an abnormal stress test without high-risk criteria without known CAD



  • Asymptomatic patients with prior MI with normal left ventricle and ischemia in the absence of high-risk criteria



  • Follow-up evaluation after cardiac transplant



  • Non–cardiac transplantation workup in patients 40 years old or older



Class III





  • Angina in patients who refuse revascularization



  • Angina in patients unsuitable for coronary revascularization or in whom revascularization is unlikely to improve the quality or duration of life



  • Screening test for asymptomatic patients



  • Postrevascularization status without evidence of ischemia



  • Coronary calcification on noninvasive testing without criteria listed earlier



Indications in Patients With Nonspecific Chest Pain


Class I





  • High-risk findings on noninvasive testing



Class IIb





  • Recurrent admissions for chest pain with abnormal (but not high-risk) or equivocal noninvasive test findings



Class III





  • All other patients with nonspecific chest pain



Indications in Acute Coronary Syndrome


Class I





  • High or intermediate risk for adverse outcomes in patients with UA unresponsive to medical therapy



  • High risk with UA



  • High or intermediate risk with UA that stabilizes with medical therapy



  • Initially low-risk UA that has high-risk features on noninvasive testing



  • Suspected Prinzmetal variant angina



Class IIb





  • Low−short-term-risk UA without high risk on noninvasive testing



Class III





  • Recurrent chest discomfort suggestive of UA without objective signs of ischemia with a normal angiogram within 5 years



  • UA in patients not deemed suitable for revascularization for whom revascularization will not lead to improved quality or length of life



Postrevascularization Ischemia Indications


Class I





  • Suspected acute failure of coronary angioplasty or stenting after PCI



  • Recurrent angina or high-risk criteria on noninvasive testing within 9 months of percutaneous revascularization



Class IIa





  • Recurrent symptomatic ischemia within 12 months of CABG



  • High-risk criteria after CABG



  • Recurrent angina after revascularization refractory to medical therapy



Class IIb





  • Asymptomatic post-PCI patients with suspected restenosis but without noninvasive high-risk test features



  • Recurrent angina in absence of high-risk features on noninvasive testing more than 1 year after CABG



  • Asymptomatic post-CABG patients with deterioration in noninvasive test parameters in the absence of high-risk features



Class III





  • Post-CABG symptoms in patients not deemed suitable for repeat revascularization



  • Routine angiography in asymptomatic patients after PCI or surgery



Acute ST-Segment Elevation Myocardial infarction


Class I





  • ST-elevation MI in patients who are eligible for primary or rescue PCI



  • Patients with cardiogenic shock who are suitable for revascularization



  • Patients for surgical repair of ventricular septal rupture or severe mitral regurgitation



  • Ongoing hemodynamic or electrical instability



Class III





  • Coronary angiography not indicated in patients deemed unsuitable for revascularization (e.g., because of severe comorbidities)



Acute Coronary Syndrome Unstable Angina and Acute Non–ST-Segment Elevation Myocardial Infarction


Class I





  • Diagnostic angiography with intent to perform revascularization in UA and non–ST-segment elevation MI with refractory angina or hemodynamic or electrical instability



  • Patients directed toward an early invasive strategy



Class IIb





  • As part of an invasive strategy for patients with chronic kidney disease



Class III





  • Diagnostic angiography as part of an invasive strategy not indicated in patients deemed unsuitable for revascularization (e.g., because of severe comorbidities)



  • Patients with acute chest pain and a low likelihood of acute coronary syndrome



  • Patients who refuse an invasive strategy



Perioperative Evaluation for Noncardiac Surgery


Class I





  • Patients with known or suspected CAD



  • High-risk features on noninvasive testing



  • Angina refractory to medical therapy



  • UA



  • Equivocal noninvasive test results in high–clinical risk patients undergoing high-risk surgery



Class IIa





  • Multiple intermediate–clinical risk features and planned vascular surgery



  • Ischemia on noninvasive testing without high-risk features



  • Equivocal noninvasive test result in intermediate–clinical risk patient with planned high-risk noncardiac surgery



  • Urgent noncardiac surgery after recent acute MI



Class IIb





  • Perioperative MI



  • Stable CCS III or IV angina and planned low-risk surgery



Class III





  • Low-risk noncardiac surgery, in patients with known CAD without high-risk features on noninvasive testing



  • Asymptomatic patients after coronary revascularization and excellent exercise capacity (≥7 METS)



  • Patients deemed unsuitable for revascularization (e.g., because of severe comorbidities)



Patients With Valvular Heart Disease


Class I





  • Before valve surgery or balloon valvotomy in patients with chest discomfort or noninvasive ischemia, or both



  • Before valve surgery in patients with multiple risk factors for CAD



  • Infective endocarditis with evidence of coronary embolization



Class IIb





  • During LHC before atrioventricular valve or mitral valve surgery in patients without symptoms or noninvasive features of CAD



Class III





  • Before surgery for infective endocarditis in patients with no evidence of coronary embolization or risk factors for CAD



  • Asymptomatic patients without planned surgery



  • Before cardiac surgery when preoperative LHC is unnecessary and patients have neither risk factors for nor evidence of CAD



CABG, Coronary artery bypass grafting; CAD, coronary artery disease; CCS, Canadian Cardiovascular Society; LHC, left heart catheterization; MET, metabolic equivalent; MI, myocardial infarction; PCI, percutaneous coronary intervention; UA, unstable angina; VT, ventricular tachycardia.





Patient Evaluation before Angiography


Before performing diagnostic coronary angiography, the physician should be fully aware of the patient’s complete medical history and indications for proceeding to PCI if necessary. In particular, the physician must have a detailed discussion regarding the risk-to-benefit ratio of angiography with or without PCI before the patient receives sedatives. This discussion may not always be possible in the emergency setting, in which prompt revascularization with minimal delay is mandatory (e.g., ST-segment elevation myocardial infarction). Nevertheless, a focused history can elucidate key details such as allergies, risk of bleeding, and increased risk of potential adverse effects (e.g., contrast-induced nephropathy [CIN], arterial access difficulties), in addition to providing the opportunity to allay patient’s concerns and obtain informed consent. The patient should also be given a brief step-by step-account of what he or she can expect to experience in the cardiac catheterization laboratory.


Physical examination should include, at a minimum, detailed vital signs (e.g., blood pressure, heart rate) and evaluation of cardiovascular, respiratory, and peripheral arterial systems. The results of these evaluations will influence arterial access choice, level of sedation, and suitability to proceed with percutaneous revascularization if deemed necessary. Results of basic laboratory tests such as renal function, complete blood count, coagulation profile, and liver function parameters should be available and reviewed. Abnormalities may require case deferral, depending on the clinical setting. Box 2-2 shows contraindications to cardiac catheterization.



BOX 2-2

Contraindications to Cardiac Catheterization





  • Coagulopathy



  • Anemia



  • Electrolyte abnormalities



  • Contrast allergy



  • Worsening renal dysfunction



  • Decompensated heart failure



  • Infection around planned arteriotomy site



  • Uncontrolled severe hypertension






Cardiac Catheterization


Coronary angiography is performed in a fully equipped specially designed catheterization laboratory (see Fig. 2-3 , A ). For minimally invasive cardiac procedures to be performed in a safe and efficient manner, a dedicated, fully trained multidisciplinary team including cardiac nurses, technicians, and an interventional cardiologist is required. Common femoral arterial sheath placement using the modified Seldinger technique remains the most frequently employed access route for coronary angiography in the United States. Despite a surge of interest in using radial artery access, ACC National Cardiovascular Data Registry data suggest that less than 2% of all cardiac catheterization procedures are performed using the radial approach. Safe arterial access before any cardiac catheterization procedure is of critical importance to the success of the entire diagnostic or subsequent PCI procedure. A thorough knowledge of this procedure and its potential complications ( Table 2-1 ) is mandatory for all operators. Femoral arterial access complications may lead to limb viability compromise and even death in severe cases.



Table 2-1

Femoral Arterial Access Complications

Data from Antman EM, Anbe DT, Armstrong PW, et al. ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction—executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 1999 Guidelines for the Management of Patients with Acute Myocardial Infarction). J Am Coll Cardiol. 2004;44:671-719; Tobis JM, Mallery JA, Gessert J, et al. Intravascular ultrasound cross-sectional arterial imaging before and after balloon angioplasty in vitro. Circulation. 1989;80:873-882; and Uren NG, Melin JA, De Bruyne B, Wijns W, Baudhuin T, Camici PG. Relation between myocardial blood flow and the severity of coronary-artery stenosis. N Engl J Med. 1994;330:1782-1788.












Diagnostic Cardiac Catheterization: Vascular Complications 0.40% Overall Complication Rate
PCI
Femoral access hematoma (>6 cm)
Retroperitoneal hematoma
Pseudoaneurysm
Atriovenous fistula
Infection
5-23%
0.15-44%
0.5-6.3%
0.2-2.1%
<0.1%


What Is the Risk Associated With Arterial Access in My Patient?


Several patient- and procedure-specific features may be used to estimate an increased risk of vascular access complications in patients who subsequently require PCI ( Box 2-3 ). Patients undergoing vascular access for diagnostic angiography alone are deemed at low risk for complications (<1% complication rate). These procedures usually entail the use of smaller arterial sheaths, often with no systemic anticoagulation. Other characteristics of low risk include elective procedures, male sex, normal renal function, and short procedure duration. Patients at moderate risk (1% to 3%) of vascular access complications include those undergoing routine PCI. In addition, increasing age, female sex, renal impairment, use of larger arterial sheaths (6 to 7 Fr), anticoagulation, and antithrombotic treatments are associated with greater risk. High-risk (>3%) features are coexisting peripheral arterial disease (PAD), renal and coagulation abnormalities, increasing age and sheath size (≥8 Fr), and female sex. Furthermore, emergency and challenging procedures such as primary or multivessel PCI and complex prolonged procedures increases the vascular access complication profile. Procedures that require even larger arterial sheaths, such as balloon aortic valvuloplasty (≥10 Fr), may carry an access complication rate of 11% to 17%.



BOX 2-3

Risk for Vascular Complications During Percutaneous Coronary Intervention

Data from Antman EM, Anbe DT, Armstrong PW, et al. ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction—executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 1999 Guidelines for the Management of Patients with Acute Myocardial Infarction). J Am Coll Cardiol. 2004;44:671-719; and Arzamendi D, Ly HQ, Tanguay JF, et al. Effect on bleeding, time to revascularization, and one-year clinical outcomes of the radial approach during primary percutaneous coronary intervention in patients with ST-segment elevation myocardial infarction. Am J Cardiol. 2010;106:148-154.





  • Advanced age



  • Female sex



  • Smaller body surface area



  • Congestive heart failure, coagulopathy, chronic obstructive pulmonary disease, renal impairment, liver dysfunction, immunosuppression, prior coronary artery bypass grafting



  • Urgent or emergency procedure



  • Multivessel coronary artery disease



  • Intraaortic balloon pump counterpulsation use



  • Antiplatelet therapy (e.g., antiglycoprotein IIb/IIIa agents)



  • Increased lesion complexity




Guide to Obtaining Arterial Access


The anatomic landmarks necessary for safe common femoral arterial access are illustrated in Figure 2-1 , A , and should be identified before puncture. The inguinal ligament usually lies inferior to the inguinal skin crease and is crossed by the femoral artery at the one third medial–two thirds lateral point. The relation of the inguinal skin crease to the midfemoral head is routinely assessed radiographically with artery forceps (see Fig. 2-1 , B ). This assessment is particularly important because considerable variation in distance may exist between the inguinal skin crease and the inferior border of the femoral head, especially in obese patients.




Figure 2-1


A, Illustration of the ideal common femoral artery (CFA) access site in relation to relevant anatomic landmarks, including the femoral head and inguinal ligament. B, Anteroposterior fluoroscopic image illustrating the forceps landmarks (midfemoral head) for the appropriate access site. C, Postaccess arteriogram in the right anterior oblique (RAO) projection demonstrates ideal CFA access. D, RAO projection in a different patient demonstrates calcified atherosclerotic CFA plaque. SFA, superficial femoral artery. E, RAO projection in a different patient demonstrates high artery entry leading to a retroperitoneal hematoma with resultant compression of the bladder filled with contrast.


An example of equipment commonly used is shown in Figure 2-3 , B. After informing the patient of what to expect, the clinician administers 10 to 12 mL of 2% lidocaine subcutaneously, initially with a 25-gauge needle and then with a 22-gauge needle over the chosen skin puncture site. Care must be taken always to aspirate before injection, to avoid intraarterial or venous lidocaine administration. Once sufficient local anesthetic has been given, all remaining agent is discarded, to avoid mistaken intravascular administration at a later stage during the procedure. A small superficial nick using the tip of a number 11 scalpel is made; this nick can then be enlarged with blunt dissection using mosquito forceps. Care must be taken to avoid trauma to the femoral artery, especially in very thin patients.


Remembering the relation of the skin entry site to the inferior femoral head, the operator holds an 18-gauge needle to the skin, usually at a 30- to 45-degree angle, while the left index and middle fingers palpate the chosen arteriotomy site. The femoral pulse is usually approximately 2 cm inferior to the inguinal ligament. The needle is then advanced slowly toward the chosen arteriotomy site until resistance is met and the needle is felt to puncture the anterior wall. Brisk arterial flow should then be encountered. Care must be taken not to puncture the posterior wall of the artery because this may potentially lead to serious complications such as hematoma or retroperitoneal hemorrhage, especially if a subsequent PCI necessitating full anticoagulation is performed. Furthermore, bleeding from a back wall puncture may initially be unrecognized until hemodynamic compromise occurs.


Using his or her right hand, the operator advances a long 0.035-inch J-tipped wire through the needle while the left hand carefully fixes the needle in position within the artery. Use of a long 0.035-inch guidewire with a soft atraumatic tip, such as the Hi-Torque Versacore guidewire (Abbott Vascular, Abbott Park, Ill), is advisable, especially in patients with known or likely PAD. The wire should advance smoothly, without resistance. If any resistance is encountered, the wire should be withdrawn and spun while it is advanced slowly under fluoroscopic guidance, thus ensuring that the wire tip moves freely and is not subintimal. If this maneuver is not possible, the wire should be withdrawn, and pulsatile needle blood flow should be confirmed. If the needle blood flow is poor or absent, the operator may try carefully repositioning the needle by changing the angle of entry. If satisfactory blood flow cannot be achieved, the best approach is to withdraw the needle completely and maintain thorough hemostasis with firm manual compression for 5 to 6 minutes or until oozing ceases.


Once the first 5 to 10 cm of the guidewire is advanced, then the operator continues to advance the wire under fluoroscopic guidance to the descending thoracic aorta. The needle is removed, and pressure is applied with the left hand to maintain hemostasis over the arteriotomy site, while the guidewire is cleaned with a sterile, nonfibrous swab and loaded with the chosen sheath. The sheath is then advanced into the artery smoothly, with gentle rotation to reduce resistance if necessary. When any extra resistance is encountered, the sheath should not be advanced without examining its position and that of the guidewire under fluoroscopy. This is also the case if any undue discomfort is experienced by the patient. After allowing the sheath to bleed back, the operator should consider performing check femoral angiography in the right anterior oblique (RAO) projection with the guidewire in situ (see Fig. 2-1 , C ). The guidewire may be directed medially by using a towel to aid identification of the arteriotomy site under fluoroscopy. When a long sheath is used, it is advanced approximately 10 cm before femoral angiography and then readvanced over the reinserted dilator and indwelling guidewire.


Checking femoral angiography at the outset of the procedure serves many uses. It identifies femoral artery anatomy and the presence of significant PAD ( Box 2-4 ; see Fig. 2-1 , D [e.g., calcification, tortuosity]), and it may prove vital in minimizing vascular complications if the patient requires PCI, in which larger sheaths may be needed. It also aids identification of possible complications, such as pseudoaneurysm formation in the case of low arterial puncture, and likely difficulty with manual compression and risk of hematoma or retroperitoneal hemorrhage in the case of high arterial puncture. For example, Figure 2-1 , E , demonstrates a high puncture with bladder compression from an extensive retroperitoneal hemorrhage. Femoral angiography is advised to assess for suitability before arterial closure device use.



BOX 2-4

Problem Solving: Common Femoral Artery Access in Presence of Peripheral Arterial Disease




  • 1.

    Aim to use the common femoral artery on the side with less PAD, if possible (stronger pulse, lesser claudication or objective evidence of lower PAD burden on the basis of arterial noninvasive testing, computed tomography angiography, or prior angiography).


  • 2.

    Identify key anatomic landmarks carefully as in item 1.


  • 3.

    Perform arterial entry under fluoroscopic guidance.


  • 4.

    Use a 0.035 steerable long guidewire with an atraumatic tip (e.g., Versacore wire, Abbott Vascular).


  • 5.

    Use a long sheath (23 cm at a minimum).


  • 6.

    Perform femoral angiography on successful sheath placement.


  • 7.

    Always exchange catheters over the guidewire by using the desheathing technique.


  • 8.

    When significant atherosclerotic disease is present at the arteriotomy site, avoid all active arteriotomy closure devices.



PAD, Peripheral arterial disease.



Radial Access


The radial approach for coronary angiography was initially described in 1989 by Campeau. Three years later, elective PCI through this approach was detailed by Kiemeneij and associates. Radial access as the default strategy has been embraced widely in many centers because of perceived benefits regarding patient comfort, early mobilization, and discharge, together with a significant reduction in morbidity and mortality after PCI in some series. Jolly and colleagues demonstrated a greater than 70% reduction in major bleeding rates with radial versus femoral access for diagnostic angiography or PCI. Significant bleeding as a consequence of femoral access vascular complications has been shown to have a negative impact on long-term survival mainly because of increasing 30-day mortality. Doyle and associates reviewed outcomes in more than 17,900 patients and found that greatest risk was seen with patients requiring transfusion of 3 or more units of blood. The most effective method of reducing the rate of major hemorrhage appears to be to employ the transradial approach. By virtue of its anatomy, the radial artery is very superficial and is not surrounded by any large veins or nerves, thus facilitating easy puncture and hemostasis. In addition, when the palmar arch is patent, the radial is not functionally an end artery, and so the hand should not be susceptible to ischemic complications should occlusion occur ( Fig. 2-2 , A and B ). Given these data, the obvious question is this: Why is the radial approach for arterial access so infrequently used?




Figure 2-2


A, Illustration of upper extremity arteries. B, Radial-brachial angiogram in the anteroposterior projection shows normal anatomy. C, Radial-brachial angiogram in a different patient shows a proximal radial artery loop. D, Radial-brachial angiogram in a different patient shows significant catheter- or wire-induced radial artery spasm.



Figure 2-3


A, Photograph of the general cardiac catheterization laboratory setup: 1, patient draped; 2, C-arm and table controls; 3, C-arm image intensifier; 4, mobile radiation shield; 5, monitor stack incorporating fluoroscopy live and review monitors, hemodynamic and electrocardiographic monitors, and intravascular ultrasound and echocardiographic image monitors; 6, defibrillator cart; and 7, automated contrast injector. B, Prepared table equipment: 1, lidocaine syringe; 2, arterial needle with cannula and radial access scalpel; 3, 0.018-inch hydrophilic radial wire; 4, 5-Fr radial artery sheath; 5, 5-Fr Jacky radial catheter; 6, 0.035-inch 260-cm guidewire.

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Aug 7, 2019 | Posted by in CARDIOVASCULAR IMAGING | Comments Off on Coronary Angiography: Technique
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